MicroBike

Turn your micro:bit into a Game Controller.

[2017-12-10] Github page: https://github.com/musabkilic/MicroBike/
[2018-12-27] Project page: https://musab.netlify.com/projects/MicroBike
[2019-01-09] Türkçe yazı: https://blog.samm.com/microbit-projeleri-microbike/

What is it?

This project allows you to control PC games using a BBC micro:bit as the game controller. To get the code to work, you'll need a couple of extra Python modules installed onto your local machine:

• PyUserInput, "a module for cross-platform control of the mouse and keyboard in python"
• David Whale's bitio library, which "allows you to run code in Python on a PC/Mac/Linux/Raspberry Pi and interact directly with the micro:bit"

Installation

Setting up your PC

You'll need to set up the device on which the game will be played first.

1. If you don't already have Python, download Python 2.7 from this link
2. If you don't already have Pip, install it by following these instructions. Pip is a "package manager" for Python, and makes getting set up with Python packages really easy.
3. Get the MicroBike folder and install the required modules.

Using command line

Open a new command line window. This is called 'Terminal' on a Mac, 'Command Prompt' on Windows, and 'shell' or 'terminal' on Linux. Type the following:

git clone https://github.com/musabkilic/MicroBike

This gets the latest MicroBike code from this Git repository.

Navigate to the MicroBike folder in your command line window using the 'cd' command - you may need to change the path, depending on how you've configured git on your computer:

cd MicroBike

Next, install the required modules:

pip install -U -q -r requirements.txt

Click below to see a demonstration of this:

Setting up the bitio library

See this to set up David Whale's bitio library.

Setting up your micro:bit

Connect your micro:bit to your computer. Get the latest bitio.hex from the bitio repository, and drag this hex file to your micro:bit to 'flash' it to the device.

If you're on Windows, you'll also need to install the Windows serial driver on your computer.

Done! You can use MicroBike by typing python controller.py in your computer's command line.

How does it work?

Let's review the code for controller.py to understand how this works.

import microbit
import time
from pykeyboard import PyKeyboard

We need to import the modules to use them later. We will use 3 modules; microbit module for controlling and reading data from the micro:bit, time module for waiting for a specific time step and pykeyboard module to control the keyboard(and the game of course).

#Function for Changing a Key 
def changeKeyState(key, value, key_name):
	global keyboard_keys

	#Change Only Neccessary
	if value!=keyboard_keys[key_name]:
		if value:
			keyboard.press_key(key)
		else:
			keyboard.release_key(key)

	keyboard_keys[key_name] = value

changeKeyState is a function, it will help us to control the keyboard keys - for example if the handlebar goes left, it will press the left arrow key.

#Specify Keyboard
keyboard = PyKeyboard()
#Set Accelerometer Values
previous_values = microbit.accelerometer.get_values()
#Set Keyboard Keys
keyboard_keys = {"L":False,"R":False,"F":False,"S":False}
#Set Images
stable = microbit.Image("00000:00000:99999:00000:00000")
images = {"N": microbit.Image.ARROW_N,
		  "NE": microbit.Image.ARROW_NE,
		  "NW": microbit.Image.ARROW_NW,
		  "E": microbit.Image.ARROW_E,
		  "W": microbit.Image.ARROW_W,
		  "": stable}

We will define some variables to use them later.

#Wait for User to Press a Button
while 1:
	#Blink
	microbit.display.show(microbit.Image.ARROW_W)
	time.sleep(0.5)
	microbit.display.clear()

	#Start the Program if a Button is Pressed
	if microbit.button_a.was_pressed() or microbit.button_b.was_pressed():
		break
	time.sleep(0.5)

This is the first loop. It will keep blinking until the user presses the A or B button. After pressing the button controller will start running.

#Start the Loop
while 1:
	#Get Accelerometer Values
	accelerometer_values = microbit.accelerometer.get_values()
	x,y,z = accelerometer_values

	#Calculate Avarege Motion in X,Y,Z Directions
	motion = sum(map(lambda x:abs(accelerometer_values[x]-previous_values[x]),range(3)))/3

This is the main loop. We will start by getting required values and calculating the motion.

	#Change Direction
	changeKeyState(keyboard.up_key,y>400,"F")
	changeKeyState(keyboard.right_key,x>60,"R")
	changeKeyState(keyboard.left_key,x<-60,"L")
	changeKeyState(keyboard.shift_key,motion>500,"S")

	#Set Direction to Show
	direction = ""
	if y>400:
		direction += "N"
	if x>60:
		direction += "E"
	elif x<-60:
		direction += "W"

	#Show the Direction
	microbit.display.show(images[direction])
	#Set Current Accelerometer Values to Previous
  previous_values = accelerometer_values

Then we will use the information we get before to control the game. Keyboard keys will trigger when the microbit turns right or left higher than a specific value.

We will use same information for changing the direction on the microbit.

Musab Kılıç
@musabkilic & @musabkilic0
Licensed under the GNU General Public License v3.0